Stitch-eobmctg- mechanism eor sewing-machines



C. W. THOMAS. STITCH FORMING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED MN. 8. 1916; 1,304,627.

Patnted May 27, 1919.

WITNESSES." //Wl:'/V T70i EwuzsW 10/14/15 A45 M I, 10, 7.3M W5 ATTORNEYc. w. THOMAS. STITCH FORMING MECHANISM FOR SEWING MACHINES. APPLICATIONFIL EU MN: 8 1916 I 1,304,627. Patented May 27, 1919.

2 SHEETS-SHEET 2.

INI/E/VTOR CARLYLE 'W. THQMAS, 01? BRIDGEIEORT, CONNECTICUT, ASSIGNOB.TO THE SINGER MAHUFACTUEING COMPANY, A CORPORATION OF JERSEY.

EEZQCH-FGRBEING MECHANISM FOR SEWING-MACHINES.

neon-ear.

Specification of Letters Patent.

Patented M y 27, 1919..

Application filed January 8, 1916. Serial No. 70,901.

- To all wkome'tmay concern:

Forming'hiechanisms for Sewing-Machines,

of which the following is a specification, referencebeing had therein tothe accompanying drawings.

Q This invention relates to improvements in sewing machinestitch-forming mechanisms, more particularly that class of machinesemploying multiple needles in connection with multiple looptalcerswherein the needles are controlled to operate singly or together, andhas for its object to control the slack of the bobbin-thread during theperiod that the needle, carrying the thread being concatenated with saidbobbin-thread, is idle, such idle period occurring when the seams are tobe continued at an angle to the previously formed lines of stitching.

The present invention is directed to improving the construction of underthread controlling mechanism represented by United States Patent No.593,734, of November 16, 1897, to G. H. Colley, and differs from thedevice of the patent in the controller-spring being mounted and-actuatedindependently of the rotary movements of the bobbin, so that its limitof'action remains the same under all conditions of under thread supply,while in the patented device the thread-controlling action of thecontroller-spring depends upon the amount of thread carried by thebobbin.

Referring to the drawings which form a part of the specification, Figure1 is a view in front side elevation of the front end portion of a sewingmachine arm'bracket and bed-plate, ,the latter shown in section,equipped with one form of multiple needle stitch-forming mechanism andmeans for throwing one of said needle-bars out of action. Fig. 2. is aview in front end elevation of Fig. 1, except that it includes thebracket-arm and the bed-plate is shown in section transverse to thatshown in the latter figure. Fig. 3 is a plan view of the loop takershown at the right of the needle in Fig. 1 and its bracket or saddle,together with a like view of the cloth or throatplate. Fig. dis a viewin central section of the present bobbin-case, the sameasis shown inFig. 3, fitted with the present invention. Fig. 5 is a plan view of thepresent bobbincase, the controller-spring cap being removed to bring toview the controllerspring. Fig. 6 is an'edge View of Fig. 5. Fig. 7 isan inverted View of the bobbincase cap, together with a portion of thebobbin-stud and bobbin-thread illustrating the travel of the thread fromthe supply to and through the free end of the controller-spring. Fig. 8,views a, b, c andd show how the slack thread is formed and latercontrolled by the controller-spring. Fig. 9 is a specimen productillustrating angularly arranged parallel seams.

The present invention is herein shown and described as applied to aSinger 108W class machine fitted with multiple needlecarrying barscontrolled to operate singly or together, substantially the same as risrepresented by United States patent application of Herbert Corrall, Ser.No. 840,170, filed May 22, 1914, for improvements in sewing machines,but as the present invention is not limited in its application to anyonly such reference will be made to the elemerits comprising the latteras is necessary for a proper understanding of its construction and use.

Referring to the figures, 1 represents the sewing machine bed-plate uponwhich is mounted the bracket-arm comprising the arm-bracket 2 andstandard 3 and into the head or free-end of said bracket-arm there ismounted to move vertically the needlebars 4 and 5 provided with theusual thread needles, said needle-bars being operatively connected,through the shaft-flange 6,- needlebar actuating link 7 and needle-baractuating stud-eollar 8, with the main or needlebar actuating shaft 9. p

The stud-collar 8 is provided with two tubular openings, as 10, throughwhich pass the respective needle-bars, the latter being provided withopenings, as 11, in which is seated the teats, as 12, (the-openings l0and 11 and teat 12 being shown singly and in dotted lines only, see Fig.2) formed integral with the plunger-pins, as 13, provided with knurlednuts, as 14, and springs, as 15, '(one only of the latter being shown)which latter act to resiliently hold the teats 12 seated in the openings11.

a spring, as'l6, seated at their lower ends on the stud-collar 8, theiropposite ends being confined by collars, as 17, (one only of saidsprings and collars being shown) secured on said needle-bars, for apurpose later to bereferred to. Upon the upper surface of the head ofthe arm-bracket is secured by screw, as 18, guide-brackets, as 19,having their inner or free ends V-shaped, which latter track theV-shaped grooves, as 20, formed in the needle-bars, said brackets actingto hold the latter against accidental rotation when released fromcontrol by the teats 12 of the plungers -13.

21 represents a plate suitablysecured to the head of thearm-bracket andprovided with suitably secured brackets 22 and 23 having openings, as 24and as 25, respecti vely, (said openings being shown in dotted linesonly,-see Fig. 1) and into said openings are mounted to move verticallyrods 26 and 27 yieldingly held by springs, as 28, in their elevatedpositions, the lower ends of said rods carrying enlarged portions, as29, provided with inclines, as 30, and slots, as 31, into which lattertrack the plunger-pins 13, the upper ends of each of said rods beingprovided with depressing brackets, as.

33, for a purpose later to be explained.

34 denotes a tubular post suitably secured upon the uppersurface of thebracket-armhead and into said post is housed to move vertically a pin orplunger35 (shownv in dotted lines only, see Fig. 1) carried by aneedle-bar depressing cap 36, and to move said cap there is interposedbetween the base of the tubular post and the lower end of the pin 35 aspring 37, the movement of said cap being limited by a stop-pin 38suitably secured in said post and tracking a slot 39, formed in saidcap. 40 denotes the clothpresser carried by the cloth-presser bar 41 and42 the needle thread take-up.

When it is desired to discontinue and later resume thestitch-forming-movements of one of the needle-bars, for illustration,the one located at the right in Fig. 1 the other being controlled inlike manner, the operator, through the bracket 33, moves the rod 27downward, and in doing so causes the incline 30 to act upon the nut 14to withdraw the teat 12 of-the pin 13 out of engagement with the opening11 in the needle-bar, thus permitting the spring 16 to elevate theneedlebar slightly above its limit of upward stitch-forming movementwhere it remains with the teat 12 in contact with its solid portionuntil the opening is again brought into the field of movement of saidteat by depressing the cap 36 when, owing to the rod 27 having beenmoved to its elevated position by its spring 28, the teat is permittedto again enter the opening 11 and transmit to the needlebarstitch'forming movements.

it is thought sufficient to refer to the loop- I takers, as 43, as beingprovided with looptaker shafts, as 44 (shown in dotted lines only,Fig. 1) operatively connected by bev eled gears, as 45, with agear-shaft 46, which latter is operatively connected with the looptakeractuatin shaft 47 by gear members 48 and 49, WlllCh latter are of theratio of two to one, thus giving to the loop-takers two rotations to onecomplete actuation of the needles, the loop-taker actuating shaft beingoperatively connected with the mainshaft 9. by means (not-shown) commonto earlier constructions. 50 denotes the throat or needle-plate and 51the feed-dog operated in a manner'common to many earlier varieties ofsewing machines.

The bobbin-case comprises a' base portion 52 and cap 53, the linedividing said portions corresponding substantially with the upper wall54 of the radial fin 55, which latter is journaled in a suitableguideway (not shown) formed in the inner wall of the loop-taker, as inearlier constructions,

the exception to the dividing line being arranged as noted above beingthe providing of the bobbin-case base with an upwardly extended portion56, the upper free edge of which coincides with the base line '57-of theoval portion 58 of the bobbin-case cap and extending from-the point 59to 60, best shown in Fig. 5. The bobbin-case base is provided with theusual central hub 60 into which is housed a spring-controlled plunger 61whose upper end is provided with an en larged portion 62 which acts on alatch 63 1,95 hinged in the free end of said hub, said latch acting tohold the bobbin-case against accidental displacement, the thread-bobbin64, provided with the mass of under thread 65, being inclosed in saidbobbin-case to rotate' lo on said hub. The bobbin-case base is providedwith the usual bobbin stops, as 66, and the throat-plate with the usualstoplugs, as 67, said stops and lugs acting to hold the bobbin-caseagainst following the 5 rotary movements of the loop-taker, as inearlier constructions.

To thread the bobbin, the thread is led from the supply through theslotted notch e formed in.the rim of the bobbin-case cap 53,'th enbeneath the suitably secured thread tension spring 9, back through theslotted notch it along the inner surface of the rim f, out through theslotted notch and from the latter through the thread-eye 69, from which125 it is passed through the needle opening in the tl1roatplate.

Referring now to the features in construction more directly connectedwith the invention, 68 denotes a bobbin-thread control- 130 ler springprovided at its free end with a thread-eye 69, its opposite end beingsecured of movements of the stitch-forming mechanism relatively to thefeed movements and manual manipulation of the fabric under the needlesfor effeeting'the angularlydirected seams of Fig. 9.

Referring to Figs. 8 and 9, 76 represents the right-hand and 77 the lefthand seam; view a, Fig. 8, showing the seams advanced to their limit ofparallel relationship in a. single direction, at which point therighthand needle '78 is placed out of action and the seam 77 continuedfor a distance correspondin to the distance between said seams, asrepresented in view I), Fig. 8, when the fabric is turned about theneedle 7 9 in the direction indicated by the arrow, view c,

Fig. 8, in position to continue the seam 77 at right angles to thepreviously formed portion of the seam, and in this connection it is tobe noticed that during the idle period of the needle 78 there has beendrawn from the supply a. length 80 of free under thread extending fromone to the other of the seams. when the machine is again put into actionand the seam 77 advanced to a point in line with the seam 7 6, see view(5, Fig. 8, when the needle 78 is brought into action.

During the time that the seam 77 is being advanced from its previouslyformed angular portion to a point in line with the seam 76, thethread-controller spring has taken up the slack thread 80, see view (Z.Fig. 8, so that the needle 79 will commence its stitching operationunder normal conditions.

It is to be understood that the tln'ead-controller spring is drawn to is limit of torsional movement when first starting the seam formationand. so held during the stitching of a continuous seam except when, fromany cause, slack is formed in the bobbin-thread.

Having thus set forth the nature of the invention, what I claim hereinis:-

1. In a. stitch-forming mechanism for 'sewingn'lachines, the combinationwith a continuousl v rotating loop-taker and a stationary bobbin-case,the latter journaled in said loop-taker and provided with athread-tension mechanism and a thread-bobbin, of a thread-controllerspring carried by said bobbin-case and acting independently of saidbobbin to resiliently resist the pull upon the bobbin-thread incident toseam formation.

2. In a stitch-forming mechanism for sewing machines, the combinationwith a con-- tinuously rotating loop-taker and a stationary bobbin-case,the latter comprising a base portion provided with a cap inclosing a.thread-bobbin and having a thread-tension mechanism, of athread-controller spring carried by said cap and acting independently ofsaid bobbin to resiliently resist the pull upon the bobbin-threadincident to seam formation.

3. In a stitch-forming mechanism for sewing machines, the combinationwith a continuously rotating loop-taker .and a stationary bobbin-case,the latter provided with a thread-tension mechanism, a thread-bobbin anda spring-pocket, of a thread-controller spring mounted in said pocketand acting independently of said bobbin to resiliently resist the pullupon the bobbinthread incident to .eam formation. v

4. In a stitch-forming mechanism for sewing machines, the combinationwith a continuously rotating loop-taker and a stationa'rybobbin-case,the latter comprising a base portion and a cap, said bobbin-case beingprovided with a thread-bobbin and a thread tension mechanism and said'-cap with a spring-pocket. of a threadcontroller spring mounted insaidpocket and controlled to resiliently resist the pull upon the bobbinthread incident to seam formation.

-5. In a stitch-forming mechanism for sewing machines includingnniltiple'needles and continuously rotatingcooperating looptakers, eachof the. latter being provided with a bobbin-case and each bobbin-casehaving a thread-tension. of a thread-controller carried by therespective bobbin-cases and acting independently to resiliently control.the slack of the bobbin-case threads when directing the parallelsean'i-formations at an angle to the previously formed seams.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

CARLYLE V. TH OM A S. Vitnesses Tirnononn JoRcnNsnx, Var. A. Sanrrnn.

